The invention relates to a proportional throttle valve having the features set forth in the preamble of claim 1.
Such two-way throttle valves are known (Oelhydraulik und Pneumatik, Magazine for fluid technology, No. 8, August 1981, FIG. 2). The valve member governing the flow rate of the throttle valve is subjected in the opening sense to the inlet pressure and in the closure direction to a spring under the control pressure set at an electrically controlled pilot valve. This is thus a throttle valve with hydraulic pressure feedback.
On pressure fluctuations at the inlet or outlet of the throttle valve the position of the valve member can change if the pilot valve is unable to compensate the pressure fluctuations by corresponding variation of the control pressure. This is the case in particular with long conduits and large flow rates because large fluid volumes in such systems tend to execute oscillations which lead to corresponding pressure fluctuations.